1. Field of the Invention
The present invention relates to medical devices, and, more particularly, to a biopsy device having a ratchet drive mechanism for driving a biopsy probe assembly.
2. Description of the Related Art
A typical biopsy device includes a biopsy driver to which there is mounted a biopsy probe assembly. The biopsy driver typically is configured to be reusable, whereas the biopsy probe assembly is configured to be disposable. The biopsy driver provides the electromechanical power used to drive the biopsy probe assembly. Typically, the biopsy probe assembly has a cannula configured with a sample notch and a tissue sample chamber, and has a tissue cutting mechanism associated with the cannula. During a biopsy procedure, vacuum assistance may be used to help draw tissue through the sample notch and into the sample chamber and maximize the amount of tissue obtained with each sample. Some biopsy devices, commonly referred to as single insertion, multiple samples, or SlMS devices, utilize sample acquisition and delivery mechanisms that allow multiple samples to be acquired from a given lesion region without removing and reinserting the needle after each sample. One type of cutting mechanism used in a vacuum assisted SlMS biopsy device uses rotational and linear motion of a cutter with respect to the sample notch to sever the tissue drawn through the sample notch into the tissue sample chamber. Vacuum is applied to transport the tissue from the tissue sample chamber of the cannula to a sample collection basket. This process may be repeated until the desired amount of tissue has been obtained.
Also, such a typical biopsy device utilizes a biopsy driver having electrical power in the form of a rechargeable battery to facilitate motor driven linear and rotational movement of the cannula and/or the tissue cutting mechanism of the biopsy probe assembly. Such use of motor driven components to drive the cannula and/or the tissue cutting mechanism in the biopsy driver adds cost to the overall biopsy device.
It would be desirable to reduce the cost of the biopsy device without sacrificing the ability to consistently collect high quality tissue samples.